Table of Contents
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Table 2 below provides definitions for the entities and key properties, as well as example mappings to some agency data. The headers for the three examples link to actual data that can be used as a reference for the diversity of data being represented and how it can be modeled in the STA data model. The exercise of mapping agency data to this data model is very important to further more functional data integrations steps.
SensorThings Entity | Description | Example: NMBGMR Aquifer Monitoring Well | NMED Drinking Water Quality Monitoring | NMOSE Water Withdrawal Monitoring | ||
|---|---|---|---|---|---|---|
Metadata | Location | A unique coordinate or area on the surface of the earth | Location in latitude and longitude or UTM easting and Northing (UTM Zone 13, NAD83) | Street Address (with associated latitude and longitude) | Location in easting and northing | |
Thing | Some real-world thing with which one or more Sensors are associated | Well | Sampling Point | |||
Datastream | A collection of Observations about an ObservedProperty produced by a Sensor associated with a Thing | Time series, Hydrograph | ||||
Datastream/observationType | The type of observation, codified in the Observations and Measurements data standard. Types include Categorical (defined text), Count (integer), Measurement (continuous number), Observation (free text), and TruthObservation (True/False) | continuous number (Measurement) | ||||
Datastream/unitOfMeasurement | A three-item definition of the unit of measurement, including its name, symbol, and link to the definition. | metersfeet below ground surface (ft BGS) | ||||
Sensor | The procedure used to provide a Datastream. Can be a particular data recording device model, or a defined procedure followed by a human observer. | Diver, Wellintel, Steel-tape measurement; Continuous acoustic sounder | ||||
ObservedProperty | The raw or processed phenomenon (quantitative or qualitative) being measured for the Datastream. | Depth to Water Pressure Head, DepthBelowSurface | ||||
OPTIONAL: FeatureOfInterest | The real-world feature that the Observations are about. This may be different from the Thing on which the Sensor is mounted. Can be a point location or a polygon or collections thereof. | Aquifer (polygon) | Public Water System (head office location or service area boundary) | Water Right (set of relevant points of diversion) | ||
Data | Observation | A single measurement value including the result, time values, and other metadata. Information on the ObservedProperty that was measured by what Sensor is provided by the Datastream these observations are in. Features of Interest are linked for each observation as well. Observations are linked to (collected in) Datastreams | Depth measurement | |||
Observation/result | The actual measured value, with valid values defined in observationType and units defined in unitsOfMeasurement, both provided by Datastream | 3252337.08 | ||||
Observation/phenomenonTime | The date+time (or interval) in ISO 8601 format (YYYY-MM-DDT:HH:MM:SS-Z) when the observation occured | 2019-01-31 00:00:00 | ||||
OPTIONAL: Observation/resultTime | The date+time that the result was generated. May be the same as phenomenonTime | |||||
OPTIONAL: Observation/validTime | The date+time interval during which the Observation can be used (often used for provisional values that are replaced by QA/QC’d observations) |
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